Rotary compressor



June 23, 1970 TUNEQ MQNDEN ETAL I 3,516,766

ROTARY COMPRESSOR Filed July 10, 1958 2 Sheets-Sheet 1 FIG. I

INVENTOR) June 23, 1970 TUNEO .MONDEN ETAL ROTARY COMPRESSOR 2Sheets-Sheet 2 Filed July 10, 1966 FIG. 3

FIG. 4

INVENTORS United States Patent O US. Cl. 41863 1 Claim ABSTRACT OF THEDISCLOSURE In a rotary compressor wherein a rotor supported by aneccentric is caused to roll along the inner periphery of a hollowcylinder, a pair of annular grooves extending axially from the oppositeend surfaces of the rotor are provided near the inner periphery of therotor to permit elastic deformation of the rotor periphery.

BACKGROUND OF THE INVENTION This invention relates to a rotarycompressor and more particularly to a motor driven rotary compressor forair conditioners and contained in a hermetically sealed casing.

This type of motor compressor comprising a driving motor inserted in theupper portion of the sealed casing, a flange supporting the shaft of themotor and a compressor located beneath the flange. The compressorcomprises a cylinder, a rotor mounted on an eccentric of the motor shaftto eccentrically roll along the inner surface of the cylinder and aslide blade contained in a slot of the cylinder and urged against theouter periphery of the rotor by means of a spring whereby upon rotationof the rotor, gaseous refrigerant is sucked into a low pressure chamberin the cylinder, compressed and is then discharged into a condenser froma high pressure cham ber. As the interior of the cylinder is dividedinto the low and high pressure chambers by the slide blade the contactsurface between the inner surface and the outer surface of the eccentricwould not become a uniform surface contact but instead the loadconcentrates to some portion causing excessive wear thereof. Operationover a long period under such concentrated load not only decreases theefliciency of gas compression but also applies an overload to thedriving motor.

In accordance with this invention these troubles are eliminated byproviding a pair of annular grooves axially extending from the oppositeend surfaces of the rotor near the inner periphery thereof thuspermitting elastic deformation thereof.

The outer diameter of the eccentric may be reduced at the centralportion of the portion opposing the solid portion of the rotor betweenthe bottoms of the annular grooves.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a longitudinal section ofa motor compressor embodying this invention;

FIG. 2 shows a partial cross-sectional view of the compressor shown inFIG. 1 taken along a line IIII.

FIG. 3 is a partial view, partly in section to show the concentratedload at the contacting surface between the eccentric and the rotor of aprior art compressor;

FIG. 4 is a view, partly in section, of the rotor and eccentric showingthe distribution of said pressure;

FIG. 5 is a cross-sectional view, taken along a line V--V in FIG. 4 andviewed in the direction of arrows; and

3,516,766 Patented June 23, 1970 FIG. 6 is an enlarged view to show theelastic deformation of contacting surface between the eccentric androtor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1, arotary compressor embodying this invention is shown as comprising acylindrical hermetically sealed casing 10 in which is inserted a stator12 of a motor 13. The stator 12 is provided with a winding 17 to drive arotor 11 having a shaft 18 journaled by a frame 19 also force fit in thesealed casing. A cylinder 21 of the compressor is clamped between thelower surface 19a of frame 19 and a lower end plate 22. In a cylindercavity 23 are contained an eccentric 14 of the motor shaft 18 and arotor 15 encircling the eccentric 14. A slide blade 24 is received in aslot cut in the cylinder 21, which is normally urged against theperiphery of the rotor by means of a spring 25. Cylinder 21 has asuction port 30 communicating with a suction perforation 26, an exhaustport 31 which is normally closed by a discharge valve 32 and a highpressure discharge chamber 33 communicating with a condenser through adischarge perforation 27. As shown in FIG. 2 the lower end plate 22 isconnected to the frame 19 by bolts 29 extending through bolt holes 28.

With the prior construction, due to the above-mentioned side pressure P,the contact pressure between the rotor and the eccentric is not uniformas diagrammatically shown in FIG. 3. Thus the load is the highest at apoint C causing undesirable wear at this point and undesirable overloadof the driving motor.

As shown in FIGS. 4 and 5, according to this invention, outside diameterof the eccentric 14 is reduced about 0.1 to 1 mm., at the centralportion over a length of about Vs of the total axial length and therotor is provided with annular grooves 103 near its inner periphery,said annular grooves extending from opposite end surfaces of the rotortowards the axial center thereof.

In FIG. 4, the reduced portion of the outside diameter of the eccentric14 is shown by the reference numeral 141, portions adjacent to thebottom of said annular grooves 103 and said reduced portion 141 of theeccentric 14 being axially overlapped with respect to each other. In thearrangement shown, the eccentric 14 contacts only thin, inner peripheralwalls 106 of the rotor 15 which are disposed adjacent to a pair ofgrooves and, therefore, the side pressure applied to the eccentric isuniformly distributed as illustrated by arrows in FIG. 4.

The operation of the novel compressor is a follows: When the rotor 15 isrotated by the electric motor to compress the gaseous refrigerant, loadis concentrated at a point C shown in FIG. 6, by the side pressureacting upon the rotor 15 to deform the rotor as shown by GP, thuscausing non-uniform contact between the rotor and the eccentric.However, annular grooves 103 permits elastic deformation of thinperipheral walls 106 between the annular grooves 103 and the innerperiphery of the rotor thus causing the contact surface of the rotor toassume a position shown by CO thus assuring uniform distribution of theside pressure in the eccentric 14. Thus the undesirable effect of sidepressure is alleviated to reduce local wear and smooth operation over along time.

Since the solid portion 105 between the bottoms of annular grooves 103does not undergo elastic deformation, the diameter of the eccentricopposing this portion is reduced to make more effective the elasticdeformation. However, it will be clear that elastic deformation can bepermitted to occur without reducing the diameter of the central portionof the eccentric. Further, it is clear that the pair of annular grooves103 may be unsymmetrical.

While the invention has been shown and described in terms of a preferredembodiment it should be understood that many alterations andmodifications will occur to those skilled in the art without departingfrom the true scope and spirit of the invention as defined in theappended claim.

What is claimed is:

1. In a rotary compressor comprising a cylinder including an innerperipheral wall; an eccentric, eccentrically disposed in said cylinder;a rotor, slidably contacting said inner peripheral wall and rotatablyforce fitted around the eccentric, and a slidable blade normally urgedagainst said rotor; the improvement therein in that a pair of annulargrooves are provided near the inner periphery of said rotor and extendaxially from the opposite end surfaces of 1.)

said rotor; and at the central portion of said eccentric,

4 the outer diameter is such as to define a reduced portion thereat.

References Cited UNITED STATES PATENTS WILLIAM L. FREEH, PrimaryExaminer W. J. GOODLIN, Assistant Examiner U.S. Cl. X.R. 417424; 41881

